<html lang="en" dir="ltr">

<head>
  <meta charset="utf-8">
  <title></title>
  <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>
  <script src="https://cdn.bootcss.com/vue/2.5.17-beta.0/vue.min.js"></script>
  <style media="screen">

  </style>
</head>

<body>
  <div id="view">
  {{num}}
  <button id="cut" type="button" name="button" @click="vm.change(-5,$event)">-</button>
  <button id="add" type="button" name="button" onclick="vm.change(5,this)">+</button>

  </div>

  <script type="text/javascript">
  var vm = new Vue({
    el:'#view',
    data:{
      num:0
    },
    methods:{
      change(v,event){
        console.log(event);
        this.num += v;
      }
    }
  });

  </script>
</body>

</html>
